Voters wait in line to receive absentee ballots at the Wayne County Community College Northwest Campus in Detroit, Monday, Nov. 5, 2012. Voters flocked to local clerks offices Monday for the final day of absentee balloting with a three-to-five-hour wait in Detroit as thousands flocked to cast ballots.

Leaders of California’s powerful public employees unions on Election Day no doubt will be preoccupied with the outcome of Proposition 32, which bans automatic payroll deductions for political activity and the defeat of which has been their foremost priority.

We suspect, though, they will also keep one eye on Michigan, where voters are deciding Proposal 2, which would grant the Wolverine State’s unionized public employees the constitutional right to collective bargaining.

In a recent analysis of Proposal 2, F. Vincent Vernuccio, director of labor policy for the Michigan-based Mackinac Center for Public Policy, explained that the measure “would allow government unions to overrule at the bargaining table a multitude of laws passed by our elected representatives.”

That’s because the proposed amendment declares that no existing or future state or local law “shall abridge, impair or limit” unions’ ability to negotiate regarding “wages, hours and other terms and conditions of employment.”

Prop. 2 would make Michigan’s labor union leaders “a super-legislature,” Mr. Vernuccio said. They “would have the ability to repeal at the bargaining table many of the government management reforms,” he said, that have helped the nation’s third-most unionized state “start to turn the corner after a decade of malaise.”

Prop. 2 would have far-reaching consequences not just for the Wolverine State, but for other states as well, Mr. Vernuccio told us. The Michigan ballot measure, which has precipitated the most expensive ballot campaign in the state’s history, “is a test case,” he said, “for unions across the country.”

He predicted that if Proposal 2 wins in Michigan, California “is the next logical place” for public employee unions to put a similar measure on the ballot.

StudentsFirst, a Sacramento-based organization founded by Michelle Rhee, wife of Sacramento Mayor Kevin Johnson and a former chancellor of the Washington, D.C., public schools, is working to defeat Michigan’s Proposal 2. Ms. Rhee believes its passage will roll back school reforms that StudentsFirst and other groups have fought for.

One such reform, passed by the Michigan Legislature, ended the policy of “last hired, first fired” by which teachers are laid off in reverse order of their seniority.

Michigan lawmakers also passed a reform measure that extended the amount of time it takes for new teachers to receive tenure, while also making tenure dependent on performance evaluations, even for more experienced teachers.

Such reforms have never received a serious hearing from the California Legislature, where tremendous influence is wielded by the California Teachers Association.

It’s much the same with the California Correctional Peace Officers Assn., which has consistently gotten its way in contract negotiations with the state government. Last year, Gov. Jerry Brown signed a deal with the union that allows state prison guards to accrue an unlimited number of vacation days, which can be exchanged for cash when they leave, and at their final, usually highest, pay rate.

The governor’s concession to the union created an obligation for taxpayers with a “current cash value of $600 million,” according to the state Legislative Analyst’s Office.

California’s public employee unions already wield undue influence in Sacramento. If they were ever to secure a ballot measure like Michigan’s Proposal 2, they would become, in effect, an unelected fourth branch of state government.